Display device with privacy function, and method for providing privacy to a display device

ABSTRACT

A method is adapted for providing privacy to a display device. The display device is adapted to display a normal image that can be viewed in a user area within which a user is situated. The method includes the steps of: a) configuring the display device to generate information of an interference image; b) configuring a display panel of the display device to display the normal image and the interference image; and c) configuring the display device to direct the interference image toward areas outside the user area. Accordingly, the user situated in the user area is able to view the normal image, while a viewer outside the user area is able to view the interference image, thereby achieving a privacy effect.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 099110345,filed on Apr. 2, 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for providing privacy to adisplay device, more particularly to a method that utilizes aninterference image to provide privacy to a display device.

2. Description of the Related Art

Display devices are widely used in many applications, such as notebookcomputers, cell phones, digital cameras, personal digital assistants,and so on. When the display devices are used, how to prevent informationdisplayed by the display device from being viewed by other people is asignificant problem.

In a conventional method for providing privacy to a display device, ashield is attached to a display panel of the display device. By virtueof an optical film of the shield, a viewing region of the display panelis limited to a certain area at which a user may see an image displayedby the display panel such that other people situated in other areasoutside the certain area may not see the image. Alternatively, theliquid crystal of the display device is controllable to block backlightof the display device such that, aside from an expected area at which animage displayed by the display device is viewable, the image may not beviewed at other areas. It is desirable to provide other methods forproviding privacy to a display device.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a method forproviding privacy to a display device.

Accordingly, a method of the present invention is adapted for providingprivacy to a display device. The display device is adapted to display anormal image that can be viewed in a user area within which a user issituated. The method comprises the steps of: a) configuring the displaydevice to generate information of an interference image; b) configuringa display panel of the display device to display the normal image andthe interference image; and c) configuring the display device to directthe interference image toward areas outside the user area.

Preferably, in step b), a part of picture elements of the display panelof the display device is controllable to operate as display pixels fordisplaying the normal image, and a remaining part of the pictureelements of the display panel is controllable to operate as interferencepixels for displaying the interference image. In step c), an opticalpath control component is configured to direct lights emitted from theinterference pixels away from the user area and toward the areas outsidethe user area such that a viewer situated outside the user area is ableto view the interference image.

Preferably, the optical path control component is configured to blockoptical paths of the lights emitted from the interference pixels towardthe user area and to direct the lights emitted from the interferencepixels away from the user area and toward the areas outside the userarea. Particularly, the optical path control component is formed with aplurality of light-transmissive parts and a plurality of opaque parts,and a line connecting one of the interference pixels and a correspondingone of the opaque parts extends to the user area. The light-transmissiveparts permit passage of lights emitted from the display pixels towardthe user area, whereas the opaque parts block passage of the lightsemitted from the interference pixels toward the user area. Further, thedisplay device is configured to adjust positions of thelight-transmissive parts and the opaque parts of the optical pathcontrol component according to a position of the user as detected by adetector of the display device. Particularly, the display device isconfigured to determine a relative position of the user with respect tothe display device via the detector, and to adjust the positions of thelight-transmissive parts and the opaque parts of the optical pathcontrol component according to the relative position. Therefore, whenthe user moves, the positions of the light-transmissive parts and theopaque parts are adjusted such that the viewer situated outside the userarea continues to view the interference image.

Alternatively, the optical path control component is configured torefract and direct the lights emitted from the interference pixelstoward the areas outside the user area.

Preferably, in step b), the display panel of the display device isconfigured to alternately display the normal image and the interferenceimage. In step c), the display device is configured to direct the normalimage toward the user area when the display panel displays the normalimage, and to direct the interference image toward the areas outside theuser area when the display panel displays the interference image suchthat a viewer situated outside the user area is able to view theinterference image. Particularly, for directing the normal image towardthe user area and directing the interference image toward the areasoutside the user area, a backlight module of the display device includesa first light source configured to project light such that the normalimage is directed at least toward the user area, and a second lightsource configured to project light such that the interference imagetoward the areas outside the user area.

Another object of the present invention is to provide a display devicewith privacy function.

According to another aspect, a display device of the present inventionis adapted for displaying a normal image that can be viewed in a userarea within which a user is situated. The display device comprises adisplay panel, a display control module, and an optical path controlcomponent. The display panel includes a plurality of picture elementsfor image display. The display control module is electrically connectedto the display panel, and is operable to generate information of aninterference image, to control a part of the picture elements of thedisplay panel to operate as display pixels for displaying the normalimage, and to control a remaining part of the picture elements of thedisplay panel to operate as interference pixels for displaying theinterference image. The optical path control component is disposed tocorrespond to the picture elements of the display panel so as to controloptical paths of lights emitted from the interference pixels and todirect the lights emitted from the interference pixels toward areasoutside the user area.

Preferably, the display pixels for displaying the normal image and theinterference pixels for displaying the interference image arealternately arranged in one of vertical columns, horizontal rows, and aninterlaced arrangement.

Preferably, the optical path control component is a lenticular lens thatis disposed on the display panel, and that includes a plurality of firstcolumn parts registered with the interference pixels, and a plurality ofsecond column parts registered with the display pixels. The first columnparts are configured to refract and direct the lights emitted from theinterference pixels toward the areas outside the user area, whereas thesecond column parts are configured to direct lights emitted from thedisplay pixels toward the user area.

Preferably, the optical path control component is a liquid crystalshutter disposed in front of and spaced apart from the display panel.The liquid crystal shutter is formed with a plurality oflight-transmissive parts permitting passage of lights emitted from thedisplay pixels toward the user area, and a plurality of opaque partsblocking passage of the lights emitted from the interference pixelstoward the user area. The display device further comprises a detectorand a position-adjusting module. The detector is operable to detect aposition of the user. The position-adjusting module cooperates with thedetector to determine a relative position of the user with respect tothe display device, and is operable to adjust positions of thelight-transmissive parts and the opaque parts of the optical pathcontrol component according to the relative position so as to permit thepassage of the lights emitted from the display pixels toward the userarea and to block the passage of the lights emitted from theinterference pixels toward the user area.

Preferably, the optical path control component is a parallax barrierplate disposed in front of and spaced apart from the display panel. Theparallax barrier plate is formed with a plurality of light-transmissiveparts permitting passage of lights emitted from the display pixelstoward the user area, and a plurality of opaque parts blocking passageof the lights emitted from the interference pixels toward the user area.

According to a further aspect, a display device of this invention isadapted for displaying a normal image that can be viewed in a user areawithin which a user is situated. The display device comprises a displaypanel, a backlight module, and a display control module. The displaypanel is adapted for image display. The backlight module is disposed tocorrespond in position to the display panel, and includes a first lightsource and a second light source. The first light source is configuredto provide the display panel with light such that an image displayed bythe display panel is directed at least toward the user area and isviewable at the user area. The second light source is configured toprovide the display panel with light such that the image displayed bythe display panel is directed toward and is viewable at areas outsidethe user area. The display control module is electrically connected tothe display panel and the backlight module. The display control moduleis operable to generate information of an interference image, to controlthe display panel to alternately display the normal image and theinterference image, to turn on the first light source and turn off thesecond light source when the display panel displays the normal image,and to turn on the second light source and turn off the first lightsource when the display panel displays the interference image.

Preferably, the display panel is a liquid crystal panel.

According to this invention, a user situated within a user area is ableto view a normal image and not view an interference image, whereas aviewer situated outside the user area is able to view the interferenceimage, thereby resulting in a privacy effect.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will becomeapparent in the following detailed description of the preferredembodiments with reference to the accompanying drawings, of which:

FIG. 1 is a schematic view for illustrating relationship betweenpositions of a user area relative to a display device implementing afirst preferred embodiment of a method for providing privacy accordingto this invention, and an interference area;

FIG. 2 is a schematic view for illustrating components of the displaydevice;

FIG. 3 is a block diagram for illustrating hardware architecture of thedisplay device;

FIG. 4 is a flow chart for illustrating steps of the method of the firstpreferred embodiment;

FIG. 5 is a fragmentary schematic view for illustrating picture elementsof a display panel of the display device operating as display pixels andinterference pixels;

FIG. 6 is a fragmentary schematic view for illustrating a function of anoptical path control component of the display device;

FIG. 7 is a fragmentary schematic view for illustrating that positionsof light-transmissive parts and opaque parts of the optical path controlcomponent are movable when a user moves;

FIG. 8 is a schematic view for illustrating a display deviceimplementing a second preferred embodiment of a method for providingprivacy according to this invention;

FIG. 9 is a block diagram for illustrating hardware architecture of thedisplay device;

FIG. 10 is a fragmentary schematic view for illustrating a function ofan optical path control component of the display device;

FIG. 11 is a flow chart for illustrating steps of the method of thesecond preferred embodiment;

FIG. 12 is a schematic view for illustrating a display deviceimplementing a third preferred embodiment of a method for providingprivacy according to this invention, and for illustrating that an imagedisplayed by the display device is directed toward a user area;

FIG. 13 is a schematic view for illustrating that an image displayed bythe display device is directed toward areas outside the user area;

FIG. 14 is a block diagram for illustrating hardware architecture of thedisplay device; and

FIG. 15 is a flow chart for illustrating steps of the method of thethird preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 4, a first preferred embodiment of a method forproviding privacy to a display device is implemented by a display device1 shown in FIGS. 1 to 3. The display device 1 includes a control unit10, a backlight module 11, an optical layer 12, a display panel 13, amemory unit 14, an optical path control component 15, and a detector 16.As shown in FIG. 2, the backlight module 11, the optical layer 12 andthe display panel 13 are stacked in sequence from rear to front, and theoptical path control component 15 is disposed in front of and spacedapart from the display panel 13. The optical path control component 15is controlled by the control unit 10 so as to adjust a viewing angle ofthe display panel 13. The control unit 10 is operable to read the memoryunit 14 and control the display panel 13 to display an image, and iscoupled to and cooperates with the detector 16 to adjust the opticalpath control component 15. For convenience of the following description,in this embodiment, an area within which a user 400 is situated isdefined as a user area 401, and an area outside the user area 401 isdefined as an interference area 402. Further, the user area 401 and theinterference area 402 may move when the user 400 moves.

The backlight module 11 includes a light-guiding plate 111 and a pair oflight sources 112 respectively disposed at opposite sides oflight-guiding plate 111. In this embodiment, the light sources 112 arecold cathode lamps. It should be noted that the backlight module 11 isnot limited to this embodiment and may be other types of backlightmodules, such as a light-emitting-diode backlight module. The opticallayer 12 is disposed on the backlight module 11, and maybe one of abrightness enhancement film, a prismoidal lens, and a diffusion plate.Further, in other embodiments, the display device 1 may include aplurality of the optical layers 12, or the optical layer 12 may even beomitted.

The display panel 13 is disposed on the optical layer 12, and includes aplurality of picture elements for image display. In this embodiment, thedisplay panel 13 is a liquid crystal panel. However, the display panel13 may be a plasma panel or an organic light-emitting display panel thatdo not require the backlight module 11. The memory unit 14 storesinformation of a normal image, and provides the control unit 10 withrequired memory space. In this embodiment, the memory unit 14 is adynamic random access memory (DRAM).

Referring to FIGS. 1 and 3, the detector 16 is operable to detect aposition of the user 400 for determining the user area 401. Inparticular, the detector 16 may be a charge-coupled device (CCD) or aCMOS image sensor (CIS), and is adapted to capture an image of the user400 and to transmit information of the captured image of the user 400 tothe control unit 10. The control unit 10 includes a position-adjustingmodule 102 electrically connected to the detector 16 and the opticalpath control component 15. The position-adjusting module 102 is adaptedto receive the information of the image captured by the detector 16, andto implement image processing for determining a relative position of theuser 400 with respect to the display device 1 so as to identify the userarea 401 associated with the user 400. Referring to FIG. 6, the opticalpath control component 15 is formed with a plurality oflight-transmissive parts 151 and a plurality of opaque parts 152, andthe position-adjusting module 102 is operable to adjust positions of thelight-transmissive parts 151 and the opaque parts 152 according to therelative position of the user 400 in step 701 shown in FIG. 4. Thefunction of the optical path control component 15 will be describedlater. In this embodiment, the control unit is a microprocessor, and theposition-adjusting module 102 may be implemented using software. Inother embodiments, the control unit 10 and the position-adjusting module102 may be implemented using electronic circuits.

The control unit 10 further includes a display control module 101electrically connected to the memory unit 14 and the display panel 13 asshown in FIG. 3. In this embodiment, the display control module 101 maybe implemented using software or electronic circuits. The displaycontrol module 101 is operable to generate information of aninterference image. In step 702 shown in FIG. 4, the display controlmodule 101 is operable to control a part of the picture elements of thedisplay panel 13 to operate as display pixels 131 for displaying thenormal image according to the information stored in the memory unit 14,and to control a remaining part of the picture elements of the displaypanel 13 to operate as interference pixels 132 for displaying theinterference image. In particular, as shown in FIG. 5, the displaycontrol module 101 is operable to set the picture elements in oddvertical columns as the display pixels 131, and to set the pictureelements in the even vertical columns as the interference pixels 132.That is to say, the picture elements in the odd vertical columns areused for displaying the normal image, and the picture elements in theeven vertical columns are used for displaying the interference image.Certainly, the display pixels 131 and the interference pixels 132 may bealternately arranged in horizontal rows or in an interlaced arrangementin other embodiments.

It should be noted that, in this embodiment, the optical path controlcomponent 15 is a liquid crystal shutter formed with thelight-transmissive parts 151 and the opaque parts 152 as shown in FIG.6. Particularly, a line connecting one of the interference pixels 132and a corresponding one of the opaque parts 152 extends to the user area401. In step 703 as shown in FIG. 4, lights emitted from theinterference pixels 132 are blocked by the opaque parts 152, that is tosay, the opaque parts 152 block passage of the lights emitted from theinterference pixels 132 toward the user area 401. Therefore, theinterference image will not be directed toward the user area 401.Furthermore, the light-transmissive parts 151 permit passage of lightsemitted from the display pixels 131 toward the user area 401. Thus, theuser 400 situated within the user area 401 may see the normal image butnot the interference image, and other people within the interferencearea 402 may see the interference image and be disturbed thereby.Accordingly, an effect of providing privacy is achieved.

Additionally, referring to FIG. 7, when the position-adjusting module102 cooperates with the detector 16 to determine that the position ofthe user 401 has changed, the position-adjusting module 102 is operableto adjust positions of the light-transmissive parts 151 and the opaqueparts 152 according to the relative position of the user 400 withrespect to the display device 1. That is to say, the positions of thelight-transmissive parts 151 and the opaque parts 152 are adjustableaccording to the position of the user 400 detected by the detector 16.Therefore, the light-transmissive parts 151 may still accurately permitthe passage of the lights emitted from the display pixels 131 toward theuser area 401 and direct the normal image to the user area 401, and theopaque parts 152 may still block the passage of the lights emitted fromthe interference pixels 132 toward the user area 401. As a result, nomatter where the user 400 is situated, the user 400 may only see thenormal image but not the interference image. Further, since theinterference image displayed by the interference pixels 132 is stilldirected to the interference area 402 outside the user area 401, theinterference image still interferes with the people within theinterference area 402 to thereby maintain the effect of providingprivacy. Moreover, an ultrasonic detector or an infrared detector may beused for detecting the position of the user 400 so as to determine therelative position of the user 400 with respect to the display device 1in other embodiments.

Additionally, the memory unit 14 may be configured to store both theinformation of the normal image and the information of the interferenceimage such that the display control module 101 is operable to controlthe display pixels 131 and the interference pixels 132 to display thenormal image and the interference image according to the informationstored in the memory unit 14, respectively. Further, the optical pathcontrol component 15 may alternatively be a parallax barrier plate. Itshould be noted that, while the positions of the light-transmissiveparts 151 and the opaque parts 152 formed on the liquid crystal shutterare adjustable, the positions of the light-transmissive parts 151 andthe opaque parts 152 formed on the parallax barrier plate are notadjustable.

Referring to FIG. 11, a second preferred embodiment of a method forproviding privacy to a display device is implemented by a display device2 shown in FIGS. 8 to 10. The display device 2 includes a control unit20, a backlight module 21, an optical layer 22, a display panel 23, amemory unit 24, and an optical path control component 25. The backlightmodule 21, the optical layer 22, the display panel 23 and the memoryunit 24 are similar to the backlight module 11, the optical layer 12,the display panel 13 and the memory unit 14 of the display device 1described in the first preferred embodiment. It should be noted that theoptical path control component 25 of the display device 2 of thisembodiment is not adjustable, and thus the user area 401 associated withthe display device 2 within which the user 400 may see the normal imageis immovable. That is to say, a viewing angle of the display device 2for displaying the normal image is constant. The viewing angle isassociated with the user area 401, and an area outside the viewing angleis the interference area 402, i.e., a viewing angle of the displaydevice 2 for displaying the interference image.

Compared with the first preferred embodiment, the control unit 20 of thedisplay device 2 of the second preferred embodiment only includes adisplay control module 201. In this embodiment, the control unit 20 is amicroprocessor, and the display control module 201 maybe implementedusing software or electronic circuits.

In step 801 of the flowchart shown in FIG. 11, the display controlmodule 201 is operable to control apart of the picture elements of thedisplay panel 23 to operate as display pixels 231, and to control aremaining part of the picture elements of the display panel 23 tooperate as interference pixels 232 as shown in FIG. 10. Arrangement ofthe display pixels 231 and the interference pixels 232 is similar to thearrangement of the display pixels 131 and the interference pixels 132 ofthe first preferred embodiment shown in FIG. 5. In particular, thedisplay control module 201 in this embodiment is operable to set thepicture elements of the display panel 23 in odd vertical columns as thedisplay pixels 231, and to set the picture elements of the display panel23 in the even vertical columns as the interference pixels 232.

Referring to FIG. 10, the optical path control component 25 in thisembodiment is a lenticular lens formed with a plurality of first columnparts 251 registered with the interference pixels 232, and a pluralityof second column parts 250 registered with the display pixels 231. Instep 802 of the flowchart shown in FIG. 11, the second column parts 250are configured to direct lights emitted from the display pixels 231toward the user area 401, and the first column parts 251 are configuredto refract and direct lights emitted from the interference pixels 232toward the interference area 402. Optical structure of the optical pathcontrol component 25 is configured to refract the lights emitted fromthe interference pixels 232 and originally directed toward the user area401, and to direct the interference image to the interference area 402.Therefore, the user 400 situated within the user area 401 may only seethe normal image, and people situated within the interference area 402may see the interference image and be disturbed thereby. Accordingly, aneffect of providing privacy is achieved.

Referring to FIG. 15, a third preferred embodiment of a method forproviding privacy to a display device is implemented by a display device3 shown in FIGS. 12 to 14. The display device 3 includes a control unit30, a backlight module 31, a display panel 32, and a memory unit 33. Thememory unit 33 in this embodiment is similar to the memory unit 14 ofthe display device 1 of the first preferred embodiment, and detailsthereof will be omitted herein for the sake of brevity.

The display panel 32 is adapted for displaying an image. In thisembodiment, the display panel 32 is a liquid crystal panel. Thebacklight module 31 is stackedly disposed to correspond in position tothe display panel 32 so as to provide backlight to the display panel 32for displaying images. In this embodiment, the backlight module 31 is adirectional backlight module, and includes an optical light-guidingplate 311, a first light source 312 disposed at one side of the opticallight-guiding plate 311, and a second light source 313 disposed at theother side of the optical light-guiding plate 311. Techniques of thedirectional backlight module are disclosed in Taiwanese Patent No.I312883, and details thereof will be omitted herein for the sake ofbrevity. By the design of the optical light-guiding plate 311, when thefirst light source 312 is turned on and the second light source 313 isturned off, lights emitted from the display device 3 will be directedtoward the user area 401 as shown in FIG. 12. When the second lightsource 313 is turned on and the first light source 312 is turned off,the lights emitted from the display device 3 will be directed toward theinterference area 401 as shown in FIG. 13.

Referring to FIG. 14, the control unit 30 includes a display controlmodule 301 electrically connected to the memory unit 33, the displaypanel 32 and the backlight module 31. In this embodiment, the controlunit 30 is a microprocessor, and the display control module 301 may beimplemented using software or electronic circuits. In step 901 of theflowchart shown in FIG. 15, the display control module 301 is operableto generate information of an interference image, and to control thedisplay panel 32 to alternately display the normal image and theinterference image. Further, in step 902, when inputting the informationof the normal image to the display panel 32 for displaying the normalimage, the display control module 301 is operable to control thebacklight module 31 to turn on the first light source 312 and turn offthe second light source 313 so as to direct the normal image toward theuser area 401 as shown in FIG. 12. On the other hand, when inputting theinformation of the interference image to the display panel 32 fordisplaying the interference image, the display control module 301 isoperable to control the backlight module 31 to turn on the second lightsource 313 and turn off the first light source 312 so as to direct theinterference image toward the interference area 402 as shown in FIG. 13.Therefore, by directing the interference image toward the interferencearea 402, people situated within the interference area 402 will see theinterference image and be disturbed thereby, and thus an effect ofproviding privacy is achieved.

In summary, the display device 1, 2, 3 of this invention is adapted togenerate the interference image. By the above-mentioned steps andcomponents, the display device 1, 2, 3 allows the user 400 situatedwithin the user area 401 to see the normal image but not theinterference image, and makes people situated within the interferencearea 402 see the interference image. Therefore, the people situatedwithin the interference area 402 will be disturbed by the interferenceimage to thereby achieve an effect of providing privacy to the displaydevice 1, 2, 3.

While the present invention has been described in connection with whatare considered the most practical and preferred embodiments, it isunderstood that this invention is not limited to the disclosedembodiments but is intended to cover various arrangements includedwithin the spirit and scope of the broadest interpretation so as toencompass all such modifications and equivalent arrangements.

1. A display device for displaying a normal image that can be viewed ina user area within which a user is situated, said display devicecomprising: a display panel including a plurality of picture elementsfor image display; a display control module electrically connected tosaid display panel, said display control module being operable togenerate information of an interference image, to control a part of saidpicture elements of said display panel to operate as display pixels fordisplaying the normal image, and to control a remaining part of saidpicture elements of said display panel to operate as interference pixelsfor displaying the interference image; and an optical path controlcomponent disposed to correspond to said picture elements of saiddisplay panel so as to control optical paths of lights emitted from saidinterference pixels and to direct the lights emitted from saidinterference pixels toward areas outside the user area.
 2. The displaydevice as claimed in claim 1, wherein said display pixels for displayingthe normal image and said interference pixels for displaying theinterference image are alternately arranged in one of vertical columns,horizontal rows, and an interlaced arrangement.
 3. The display device asclaimed in claim 2, wherein said optical path control component is alenticular lens that is disposed on said display panel, and thatincludes: a plurality of first column parts registered with saidinterference pixels and configured to refract and direct the lightsemitted from said interference pixels toward the areas outside the userarea; and a plurality of second column parts registered with saiddisplay pixels and configured to direct lights emitted from said displaypixels toward the user area.
 4. The display device as claimed in claim2, wherein said optical path control component is a liquid crystalshutter that is disposed in front of and spaced apart from said displaypanel, and that is formed with a plurality of light-transmissive partspermitting passage of lights emitted from said display pixels toward theuser area, and a plurality of opaque parts blocking passage of thelights emitted from said interference pixels toward the user area. 5.The display device as claimed in claim 4, further comprising: a detectoroperable to detect a position of the user; and a position-adjustingmodule cooperating with said detector to determine a relative positionof the user with respect to said display device, and being operable toadjust positions of said light-transmissive parts and said opaque partsof said optical path control component according to the relativeposition so as to permit the passage of the lights emitted from saiddisplay pixels toward the user area and to block the passage of thelights emitted from said interference pixels toward the user area. 6.The display device as claimed in claim 2, wherein said optical pathcontrol component is a parallax barrier plate that is disposed in frontof and spaced apart from said display panel, and that is formed with aplurality of light-transmissive parts permitting passage of lightsemitted from said display pixels toward the user area, and a pluralityof opaque parts blocking passage of the lights emitted from saidinterference pixels toward the user area.
 7. A display device fordisplaying a normal image that can be viewed in a user area within whicha user is situated, said display device comprising: a display panel forimage display; a backlight module disposed to correspond in position tosaid display panel, said backlight module including a first light sourceconfigured to provide said display panel with light such that an imagedisplayed by said display panel is directed at least toward the userarea and is viewable at the user area, and a second light sourceconfigured to provide said display panel with light such that the imagedisplayed by said display panel is directed toward and is viewable atareas outside the user area; and a display control module electricallyconnected to said display panel and said backlight module, said displaycontrol module being operable to generate information of an interferenceimage, to control said display panel to alternately display the normalimage and the interference image, to turn on said first light source andturn off said second light source when said display panel displays thenormal image, and to turn on said second light source and turn off saidfirst light source when said display panel displays the interferenceimage.
 8. The display device as claimed in claim 7, wherein said displaypanel is a liquid crystal panel.
 9. A method for providing privacy to adisplay device, the display device being adapted to display a normalimage that can be viewed in a user area within which a user is situated,said method comprising the steps of: a) configuring the display deviceto generate information of an interference image; b) configuring adisplay panel of the display device to display the normal image and theinterference image; and c) configuring the display device to direct theinterference image toward areas outside the user area.
 10. The method asclaimed in claim 9, wherein: in step b), a part of picture elements ofthe display panel of the display device is controllable to operate asdisplay pixels for displaying the normal image, and a remaining part ofthe picture elements of the display panel is controllable to operate asinterference pixels for displaying the interference image; and in stepc), an optical path control component is configured to direct lightsemitted from the interference pixels away from the user area and towardthe areas outside the user area such that a viewer situated outside theuser area is able to view the interference image.
 11. The method asclaimed in claim 10, wherein, in step c), the optical path controlcomponent is configured to refract and direct the lights emitted fromthe interference pixels toward the areas outside the user area.
 12. Themethod as claimed in claim 10, wherein, in step c), the optical pathcontrol component is configured to block optical paths of the lightsemitted from the interference pixels toward the user area and to directthe lights emitted from the interference pixels away from the user areaand toward the areas outside the user area.
 13. The method as claimed inclaim 12, wherein the optical path control component is formed with aplurality of light-transmissive parts permitting passage of lightsemitted from the display pixels toward the user area, and a plurality ofopaque parts blocking passage of the lights emitted from theinterference pixels toward the user area, a line connecting one of theinterference pixels and a corresponding one of the opaque partsextending to the user area.
 14. The method as claimed in claim 13,further comprising configuring the display device to adjust positions ofthe light-transmissive parts and the opaque parts of the optical pathcontrol component according to a position of the user as detected by adetector of the display device.
 15. The method as claimed in claim 14,wherein the display device is configured to determine a relativeposition of the user with respect to the display device via thedetector, and to adjust the positions of the light-transmissive partsand the opaque parts of the optical path control component according tothe relative position.
 16. The method as claimed in claim 9, wherein: instep b), the display panel of the display device is configured toalternately display the normal image and the interference image; and instep c), the display device is configured to direct the normal imagetoward the user area when the display panel displays the normal image,and to direct the interference image toward the areas outside the userarea when the display panel displays the interference image such that aviewer situated outside the user area is able to view the interferenceimage.
 17. The method as claimed in claim 16, wherein a backlight moduleof the display device includes a first light source configured toproject light such that the normal image is directed at least toward theuser area, and a second light source configured to project light suchthat the interference image is directed toward the areas outside theuser area.